- sour [sour]adj.[ME soure < OE sur, akin to Ger sauer, ON sūrr < IE * suro-, sour, salty > Latvian sũrs, salty, bitter]1. having the sharp, acid taste of lemon juice, vinegar, green fruit, etc.2. made acid or rank by or as by fermentation [sour milk]3.a) cross, bad-tempered, peevish, morose, etc. [a sour mood]b) ill-disposed and bitter [sour toward former associates]4. below what is usual or normal; poor; bad [his game has gone sour]5. distasteful or unpleasant6. gratingly wrong or off pitch [a sour note]7. excessively acid: said of soil8. tainted with sulfur compounds: said of gasoline, etc.n.1. that which is sour; something sour☆ 2. a cocktail made with lemon or lime juice, sugar, and, usually, soda water [a whiskey sour]vt., vi.to make or become sour [the milk will sour, soured on life]sourlyadv.sournessn.SYN.- SOUR usually implies an unpleasant sharpness of taste and often connotes fermentation or rancidity [sour milk ]; ACID suggests a sourness that is normal or natural [a lemon is an acid fruit ]; ACIDULOUS suggests a slightly sour or acid quality [acidulous spring water ]; TART1 suggests a slightly stinging sharpness or sourness and usually connotes that this is pleasant to the taste [a tart cherry pie ] -ANT. SWEET
English World dictionary. V. Neufeldt. 2014.